The Exploding Cake
by FiercesomestDefenestrator
Summary: Oneshot. Ruby and Yang design a combustible cake for pranking purposes. Target #1: Weiss Schnee. Who will survive?


**A/N: Welcome to our first official fanfiction! The way this started out is I (Fiercesomest) wrote for Ruby, and Defenestrator wrote for Yang. We planned NOTHING, e-mailed back and forth for a while, stuck it all together, and bam. This fic was born.**

**Anyway, that's why it's a little choppy. We figured it was worth posting, though, so enjoy!**

* * *

Sunshine poured in through Team RWBY's dorm room window. The courtyard and walkways outside were empty- typical for mid-afternoon on a Saturday. The other Beacon students had most likely gone into town, or were doing whatever normal students do on a Saturday.

Ruby, however, was making a list. A very important list, in fact. She chewed the end of her pen absently. Flour. Sugar. Baking soda. Salt. Chocolate, of course. Or, well, cocoa. Whatever. A few other random things, like cinnamon, salt, and vegetable oil. "Hm..." Her red cape pooled on the floor behind her as she leaned back in the standard-issue dorm chair, balancing it precariously on two legs, "Why do I always feel like I'm forgetting something?"

Meanwhile, Yang stormed through the halls of Beacon at a brisk pace. The few fellow students still lingering about in the school quickly sidestepped out of her path as she swept by. Yes, she was on a mission and she would not be deterred. Lives were at stake. Heh. A smile flitted across her face as she imagined a nice salisbury steak. NO, now was not the time for dreaming of delicious distractions, she had to find her sister immediately. Searching the library had proved fruitless. All she found there was a sleepy Blake who had "most definitely not been sleeping" on a chair nestled in the farthest corner. Checking the training grounds proved slightly less fruitless though! Weiss's suggestion to check their dorm room marked her current destination. Had Ruby really spent the entire morning inside? With the door to their room in sight, Yang tipped forward into a full run and burst through the door with the force of a thousand punches.

"RUBY. WHAT ARE YOU DOING RIGHT NOW?"

"Ack!" Startled, Ruby crashed backwards to the hard floor in a heap. "Nothing!" she snatched her list, crumpling it and jerking her cloak free of the chair with her other hand as she scrambled upright, "I'm doing absolutely, 100% nothing and why-are-you-shouting?!"

Yang strode purposefully into the room and placed her hands firmly on Ruby's shoulders. She broke into a wide grin and winked. "It seemed the best way to indicate the dire nature of the situation of course!" She glanced briefly at the crumpled paper in her little sister's hand. D'aw, how cute! Ruby still thought she could hide things from her big sis. Hm, but she would save the tickle-interrogation for later. There were more pressing matters at hand! Her overly-serious expression returned full force as she stared Ruby directly in the eyes. "Nothing is good. 100% nothing is even better! Because..." Yang's eyes quickly shifted left and right, as if searching for possible eavesdroppers. "I desperately need your help. I need to... bake a cake."

Ruby blinked her silver eyes. "Um. What?" She was preeetty sure she had two days before Yang's birthday. Did her sister want to bake herself a cake? That was going to throw a serious wrench into her single-handedly-bake-her-sister-a-cake-for-her-birthday plan. Then again, Ruby couldn't recall Yang ever 'desperately' needing her help for anything that wasn't a practical joke, and Yang was an /expert/ baker. At least her cookies were amazing. "So... what's so dire about a cake?" She crumpled her grocery list a little more, darting a glance at the paper-strewn desk where she should have stashed it. Oh well.

"HAhaha. This is no ordinary cake. See, I had a stroke of brilliance this morning." Yang pulled Ruby into a one-armed conspiratorial side-hug. Her eyes sparkled with excitement. "Just imagine... you are sitting down to eat a delicious cake, you light the candles! Then suddenly... BOOM it EXPLODES!" She threw both arms up into the air for emphasis. "Cake everywhere! HAH! It could change the future of birthday pranks forever!" She nudged her little sister in the ribs with an elbow. "Who better to help me design it than the girl who exploded on her first day of school?"

"Ugh, I didn't do that on _purpose_," Ruby nudged back at Yang. Or shoved, rather. Then she moved to right her desk chair as the idea of an exploding cake took root in her mind. It did have potential, that was for sure. Ruby grinned at Yang, "Dearest big sister, you do realize that you're _asking_ for an explosive cake for your birthday, right?"

"Heh~" Yang stumbled back a bit before catching her balance. She crossed her arms and grinned right back. "Hmm. Yes, such is the life of a master prankster. You never know when your greatest creations will be turned against you..." Papers flew from the desk as she plopped down onto it. "But that just makes it all the more fun!" She leaned forward. "If you help me design this masterpiece, I'll let you pick our first target."

"I dunno. I mean, an exploding cake sounds cool and all, but I'd feel bad giving someone a dessert that blows up in their face," unless that someone was Yang, because, you know, sisters. Ruby rubbed the back of her neck. Seriously, it had been hard enough making friends as it was, being two years younger than everyone else AND partnered with the rather icy heiress. Ruby scooted the chair around, straddling it and resting her chin on her arms. "Maybe we could bake a back-up cake for after the prank? You know, to kind of smooth things over a bit."

"Youuu might be too sweet to be a proper prankster..." A slight smirk worked its way across Yang's features. "But you know I'll never say no to more cake!" She stood suddenly, golden hair swishing as she paced back and forth. "Now, choosing the first target is important!" Her mind flitted from friend to friend, measuring their personalities. "Jaune would be too easy... I'm not sure about Ren - he's so quiet! Nora is a little... strange. No idea how she'd react. Pyrrah might take it well! Blake could also work. But you know..." Yang paused her pacing. She flashed her teeth in a devilish grin. "For a pranking breakthrough this high-caliber. We need just as high-caliber a target... if you know what I mean~"

Conveniently, Ruby already had a recipe for cake on hand. A few adjustments, maybe a secret compartment in the center for a carefully-measured trace of Dust- or gunpowder. Whatever was on hand. She was in the process of smoothing out her grocery list on the desk so she could sketch a diagram when Yang showed her teeth in that grin that meant, if they'd been at home, she would probably be grounded for weeks in the somewhat-near future.

"Um..." Ruby grimaced, as the blonde brawler listed off their friends, except for one. "Pleeease tell me you're not thinking of Weiss. She would _kill_ me. She would kill _you_," Ruby turned to Yang, beseeching, "I would be both dead_and_ sister-less."

Yang lovingly rolled her eyes. "I dunno whether to be flattered that you care for my wellbeing, or insulted that you assume Weiss could kick _my_butt." She waved her hand. "Anyway, you worry too much, sis! We will of course be pranking in stealth mode. Ninja style~!" She struck what she assumed to be a very convincing ninja pose. "She'll never know it was us!"

Her pose faltered as a sudden flash of inspiration struck her like a thunderbolt. Yang's gears began spinning madly. "We could... we could even frame someone else as the prankster... and offer to help Weiss ninja-prank them as payback... and then frame someone ELSE for THAT prank and... oh Ruby." Joyous flames burned in amethyst eyes. "I have glimpsed infinity. A series of infinite pranks..."

"Um, Yang..." Ruby got the distinct feeling that she was witnessing the birth of a monster. Rebirth, anyway. She waved her hand in front of her sister's eyes to break her reverie, "Last time you set up a prank war, Signal's art wing ended up smelling like rotten eggs for a month. That was gross." But, she realized too late, no one had found out who was behind it. A huge success for the blonde prankster. And this really was bound to happen sooner or later- if she tried to pull rank as the team leader to stop her sister now, Yang would only try again sometime in the future, probably without asking her to join in.

Plus, the more she thought about it, the more she really _wanted_ to see how Weiss and the others would react to being pranked. And it _would_ be fun, so long as things didn't get out of hand. Ruby shifted uncomfortably, not entirely sure if she would be able to keep that from happening, "I mean, I guess if we kept things under control... a couple of pranks couldn't hurt."

Reverie broken, Yang's features shifted instantly to blinding cheer upon hearing her sister's acceptance. "YES. I knew I could count on you!" Limbs, paper, and furniture flew everywhere as she snatched Ruby from her chair into a spinning bearhug. "This is the best early birthday present ever!"

"Ack!" Ruby flailed her arms and squirmed to get free. "Okay, _okay_. Ahem," she cleared her throat, and straightened her cloak. "An exploding cake shouldn't be too hard, right? And I think the others are all busy this afternoon, so we've got plenty of time to make a prototype at least." Now that she'd made the decision to throw in her lot, she was starting to get a little excited. It showed on her face as she dug around in the scattered papers for her list, This would SO top making her sis a regular old cake for her birthday. They'd pull the prank, maybe instigate one or two more, and that would be it. No harm done, right? Right. Ruby banished the niggling doubt to the back of her mind and started brainstorming flavors and frosting types with Yang.

* * *

Later that afternoon...

"That dunce," Weiss Schnee grumbled as she picked up and sorted her notes and homework, which had _somehow_ been strewn all over the dorm room. How on Remnant had she gotten herself partnered with a human tornado? Granted, she hadn't seen Ruby do this, but there really wasn't any doubt in her mind about who was to blame. "Ugh," the heiress picked dust out of her snowy white hair after half crawling under the bed to retrieve what she thought was the remainder of her history notes, but she was still missing pages. Could they have slipped down behind Blake's bookshelf? She shoved at it ineffectually,

"Great. Just great. There's a quiz next class, and instead of studying I'm _rearranging furniture_." Or trying to. Weiss gripped the corner of the waist-high bookcase with her fingertips and jerked to get it away from the wall. She really should have brought Myrtenaster back to the room- its slender blade would fit in the narrow gap and coax out any hidden objects. A somewhat undignified use for her weapon, but certainly preferred over hauling at a bookcase like a lightweight idiot. Fortunately no one seemed to be around at the moment, or she would really give them a piece of her mind.

* * *

Slightly down the hall and around a corner, tiny crackles of static emanated from a small maintenance closet. Curled up in the corner of their "secret headquaters," Yang shifted farther into the darkened room, narrowly avoiding jabbing herself in the side on a broom handle. She fiddled with the screen of a small electronic device. There was no way she was going to watch Weiss shove herself uselessly at a bookcase in anything less than high-definition. The tiny camera her sister had placed in their dorm room's air vent earlier that day offered a near-perfect view of the whole floorspace! A smile flitted across her screen-lit face at the thought of her little sister pleading for full anonymity.

Ah, her original plan had been fantastic; bring the cake to Weiss personally, complete with a story about finding it in her own locker. "I think it's an early birthday present!" she would have said. "I'll share it with you, Weiss!" Then, light the candle, and brace for impact. It was a time-tested prankmaster tactic - prank yourself to remove suspicion! Never fails. Ruby however had other ideas, and convinced her to execute the prank under complete and utter anonymity. This posed problems! Problem one: How would they even see the prank happen? Ruby's solution: "Borrow" a miniature surveillance camera set from Beacon's reconnaissance building. Problem two: How would they get her to light the candle? Ruby's solution: Place the cake in a box and engineer a candle with a motion sensor that would light itself upon the lid being opened. She had even devised a cake icing that wouldn't stain clothing.

It was like pranking in hard mode, and Yang loved every second of it. She hadn't worked this hard for a prank since her heyday in Signal! Footsteps down the hall caught her ear and she glanced at the crack of light under the door. Ruby must be back from setting the trap! Her heart swelled with pride - that girl was definitely the fastest person in this school, if not the WORLD. Her eyes returned to the screen in front of her - only to see the door to their dorm swing open, revealing a familiar black bow.

* * *

Blake strolled down the halls of Beacon at a leisurely pace, heading for the dorms. Yang's interruption earlier that day had ruined her secret catnap (and her mood for a little while), so she had spent the rest of the afternoon browsing the library for a book with some light comedic value. Inspecting the back cover of her newest acquisition, she barely missed the swish of a red and black cape rounding the corner as she arrived at her shared dorm room. Fortunately, she didn't miss the plain white box siting right in front of the door. Well now that was strange. She picked it up, handling it with care as she inspected the mysterious white box from all sides. A note stuck to the side read only "To: Weiss. A sweet for a sweetheart". Well now that was even stranger. Sounds of grumbling and complaining from the other side of the door alerted her to someone's presence in the room. Blake cradled the box and her book in one hand and pushed the door open. She stared at yet another strange sight.

"Weiss... What are you doing to my bookcase?"

Weiss snapped upright, away from the stubborn set of shelves, the flicker of mortification in her face morphing into a scowl, "What does it _look_ like I'm doing? Making it tea?" she snarled, "Help me move it away from the wall."

* * *

Ruby raced back down the hall, nerves frayed almost beyond all reason. She'd just barely gotten out before Blake had seen her, and really this whole pranking thing was seeming like a worse and worse idea as she went along. "Borrowing" the camera had been a stroke of genius, but they probably didn't have long before someone realized it was missing, and now... oh, shoot. She pulled up short as she turned the corner down the hall to the maintenance closet. Was that Professor Ozpin? Ruby ducked back around the corner to watch as he paused outside the closet door.

"Hm..." Professor Ozpin folded his scroll. It had been a relaxing evening so far- there had been no major crises in the past few days, only minimal injuries sustained during the afternoon classes, and for once he was on top of his more mundane affairs. He'd even gotten his emerald green neck kerchief dry cleaned- a detail he had long overlooked in favor of other, more pressing matters. Heading up Vale's top monster hunting school wasn't all bunnies and roses. Granted, there were a few of those, but they came with paperwork. In some instances_, lots_ of paperwork.

He paused on his walk, suddenly aware of an odd sound. It took a moment to locate it- a faint crackling emanating from the door of a maintenance closet. He took a long sip of his coffee and knocked lightly.

* * *

Back in the dorm room, Blake's left eyebrow twitched, the sole outward expression of her hackles rising at Weiss's tone. She stuffed the anger back down as quickly as it arose. It would accomplish nothing to be cross with Weiss, seeing as the white-haired fencer already seemed fairly cross herself. The reason behind which she didn't particularly care to find out. Though... the tiniest hint of a smile tugged at the corner of her mouth, perhaps Weiss had also experienced a run-in with one of the sisters today. A quick glance at the veritable disaster area that was once their room told her all she needed to know. Honestly, those two were each whirlwinds in their own right.

Regardless, she had to admit it was fairly amusing seeing the heiress so flustered over a piece of furniture. Perhaps she could add to the experience. Blake crossed the room without a word and placed herself directly between Weiss and her bookcase. She gently shoved the mysterious white parcel into Weiss's arms, making sure the note on the side was visible. "This was sitting outside the door. It would seem you have a secret admirer."

* * *

Nerves and excitement battled for control in Yang's brain as amethyst eyes widened in anticipation at the view on the card-sized screen clutched in her hands. Blake. What was she doing back so early? The cool, reserved Faunus was an unknown in this pranking scenario, and unknowns either spelled trouble, or added that extra dash of thrill. Eyebrows rose to meet her hairline as she watched Blake hand Weiss something distinctly square and white and - no doubt about it that was definitely The Box. Ruby had been successful! Awesome! Yang glanced back at the closet door. Where _was_she anyway? Speak of the devil, she heard footsteps pause just outside. What was she doing? She was going to miss the main event!

Tap. Tap. Tap.

Yang blinked. Why on earth was Ruby knocking? That weirdo - she stood and pulled the door open with a lop-sided grin. "Ruby, get in here what are you... doing." Not Ruby not Ruby _not Ruby_. Her brain short circuited at the sight of Professor Ozpin himself, emerald green neck kerchief and all, standing directly before her. She slammed the door in his face.

* * *

"Don't change the subject," Weiss shot Blake a scathing glare and regarded the box in her arms with an air of utter disdain. Sweets for a sweetheart? Please. She strode to the trashcan with every intention of dumping the ridiculous package, but the dimensions were all wrong so she had to settle for wedging one corner of it in and leaving the rest sticking up.

* * *

Yang had shut the door in Ozpin's face.

_Not good, not good, not good._ Ruby bit her lip and wracked her brain for a way to get her sister out of the mess she was in. A light came on. Ha! She snapped her fingers. She had a plan. Sort of.

Ozpin stared at the door, bemused. He had certainly had a few doors shut in his face over the years, though he was fairly sure none of them had been doors to maintenance closets. Very curious indeed.

Before he could knock again and inquire as to why a Beacon student was ensconced in a dark closet, a dusting of rose petals fluttered through the air as one Ruby Rose came skidding to a halt. She was flushed and breathing hard.

"Oh, Professor Ozpin," she greeted him with a disarming smile. "You haven't seen Yang, have you? My sister?" she added in a stage whisper, "We're playing sardines."

Ozpin raised an eyebrow, "Sardines?"

"It's like hide and seek," Ruby seemed a little caught off guard that he didn't know the game, "We, uh, thought it would be a good way to practice our tracking. You know. In case there are ever any Grimm in the school and... we... have to find them."

Well, that was one of the more original cover stories he'd heard today. Static crackled in the moment of silence that followed. He took another sip of coffee. "And pray tell me what the Grimm would be doing with electronic surveillance equipment?"

"Um..."

He watched her falter for a moment, attempting to decide exactly how hard he should be on the young girl.

* * *

A quiet sigh escaped Blake's lips. That was just about the reaction she had expected from the icy heiress. She almost felt bad for the mysterious would-be admirer. "Fine then, at least tell me why you need my bookcase moved so badly - look, it isn't even that difficult." She grabbed the edge of the bookcase's side and slowly swung it around with a light bit of effort. "You just move one side at a time like thi- oh wow."

Papers, pencils, and a myriad of small items littered the floor where her bookcase once stood. Most of them seemed fairly new, they had probably been knocked behind here recently, but a particularly grimy, dusty old comb covered in long yellow hairs made her grimace. How long had _that_ been there? She picked the offending item up off the floor with the bare minimum of two fingers. This was definitely beyond redemption. Blake tossed it over Weiss's head at the trashcan, only to see it bounce off the discarded mystery-box, knocking the white lid askew before clattering to the floor. Another sigh. "You could have at least broken the box down before taking up all the space in the-" She paused. Sniffed the air once. Twice. "Do you smell something burning?..."

* * *

Yang stood frozen with her hand resting on the doorhandle. It was still sinking in that she had just slammed a door in her headmaster's face. More footsteps approached, and she heard Ruby's voice... saying something about... Sardines? Oh man she had to get out there and DO something. If there was one thing her sister was terrible at, it was fibbing. She had no idea how strict or lenient Ozpin was when it came to rule breakers, but be it one hour of detention or months of scrubbing bathrooms with a toothbrush, she could not let her little sister take the fall for this. The surveillance screen in her hands crackled so loudly she nearly dropped it. She leveled a glare at the screen. Wait, was that... did Blake just... Oh jeeze, she only had seconds. Time to do what she did best - wing it!

She threw the door back open and started speaking a mile a minute. "RUBY, there you are! I have a confession to make, see, I used playing sardines with me as a cover story when really I just wanted to show you THIS." She quickly shoved the screen into her little sister's hands before immediately turning to face Professor Ozpin. "Professor, I've been developing a new weapon to use against the Grimm but I wanted to test it out on my teammates before presenting my findings so I went behind my team leader's back and borrowed a surveillance camera to record the results," She bowed. "I apologize." If she was lucky, maybe he would let her off with a warning.

A thundering explosion shook the very foundations of the dorms. Yang was pretty sure she saw their door go flying past the end of the hall. Hm. They might have used too much Dust. Well, maybe she would get off with just being banished from the planet.

* * *

Two days after the explosion...

"Happy birthday, Yang," Ruby groaned from her position face-down on the mattress on the floor. Unfortunately, their bedframes had been compromised in the explosion. As in destroyed.

Ozpin was psychic. It was the only explanation for his being able to figure out exactly what had happened so _quickly_. That and she _was_ a terrible liar. Oh well. He'd seemed about to let them off with a smile and a wink when Professor Goodwitch had showed up. Ruby grimaced at the memory. Glynda was even scarier than Weiss... who had been pretty scary after she'd gotten over the concussion she'd sustained from being present at ground zero.

As it was, Ruby had just barely survived the scoldings, the lectures, and the special, intensive punishment-for-developing-unsupervised-weapons-and-blowing-up-the-dorm combat practice Professor Goodwitch had scheduled on top of her regular combat practice and classes for the rest of the semester. She hadn't even showered, but she didn't care. Everything hurt. "Let's never do that again."

"Never again sounds good," came Yang's muffled reply. Dressed in the finest business suit she had ever been loaned, she too found herself face-down on her sleeping bag on the floor. Presentations. UGH. How had they known her weakness?! Lectures? In one ear and out the other. Physical labor? That was her favorite! But when Ozpin had approached her with a pressed suit and that twinkle in his eye, she knew she was done for. Apparently he had been "so impressed" with her "new weapon" that he wanted her to present her "research and findings" to the school board so that it could be added permanently to Beacon's armory. Not even Weiss's murderous glare from across the infirmary could come close to the horror of formal business presentations.

Her thoughts shifted as she remembered her visit to the infirmary. She had gone to visit Blake to make amends. Deep down she knew that however livid Weiss seemed, she would eventually get over being pranked, but Blake was still somewhat of a mystery to her. For the sake of the team (and because they were bunkmates), she wanted to make sure there was no bad blood between them. Their conversation replayed itself in her head.

"Heyyy Blake, so how's that uh, light concussion treating you? Sorry you got caught in the crossfire."

"It's fine. ... I never expected you to be Weiss's secret admirer."

"What?... What!? Oh jeeze no, the cake box? No, nope, she is NOT my type at all. That was just part of the cover story, there is no wa-"

"Next time... ... next time use cupcakes. That way, you can hit multiple targets at once.. and expand the blast radius without having to increase the blast intensity."

Blake had then promptly rolled over and gone to sleep. Jaw firmly planted on the floor, Yang had sat and stared at the sleeping Faunus for probably a solid minute afterwards.

Yang flopped over onto her back. A grin slowly spread across her face. Beacon may have won this battle, but maybe she could yet win the war.

* * *

**A/N: I hope this hasn't destroyed your trust in cake forever.**

**Hugs,  
****Defenestrator**


End file.
